1. Field of the Invention
The present invention relates to a method and apparatus for transmitting broadcast data and a method and apparatus for receiving broadcast data, and more particularly, to a method and apparatus for transmitting broadcast data and a method and apparatus for receiving broadcast data so as to provide a broadcast service according to the Open Mobile Alliance-BroadCAST (OMA-BCAST) standard.
2. Description of the Related Art
Recently, digital broadcasting that provides various additional data services such as weather, traffic, entertainment, and images etc., as well as high-quality audio services corresponding to the sound quality of a compact disc (CD) have become widely popular. In particular, a broadcasting technology in which digital broadcasting is used with a mobile device has been spotlighted.
An 8-level Vestigial SideBand (VSB) transmission system for digital broadcasting is defined in the Advanced Television System Committee (ATSC) standard, and an Advanced-Vestigial SideBand (A-VSB) system is used as a more developed format of 8-VSB. In the 8-VSB transmission system, 8-step modulation signal levels and vestigial side band modulation technologies are used, and image signals are compressed according to the MPEG-2 standard, and voice signals are compressed according to the AC-3 standard. 18 signal formats are variously used in such method. Thus, broadcasting of several channels can be transmitted simultaneously.
Meanwhile, due to the development of digital transmission technology, broadcasting communication fusion services for providing broadcasting services and communication services using the same terminal unit have been spotlighted. In the Open Mobile Alliance-BroadCAST (OMA-BCAST) standard, content is provided to a terminal through Internet Protocol (IP)-based packets, and the provided content may be transmitted via a communication net as well as via a broadcasting net.
However, in the case where packets are transmitted via a broadcasting net, positions of packets to be obtained cannot be easily searched. Thus, a conventional apparatus for receiving broadcast data receives all packets and then extracts desired packets from the received packets by using header information of the packets etc. Thus, it is very inconvenient to use the conventional apparatus for receiving broadcast data in a broadcasting system in which the position of desired data must be quickly determined and processed.
In particular, a Service Guide (SG) for providing additional information about broadcasting services such as an electronic program guide (EPG) and an SG announcement for providing metadata about the SG are defined in the OMA-BCAST standard. Packets including an SG announcement and packets including the SG must be sequentially processed so that desired broadcasting services can be effectively provided to users. However, in a conventional broadcasting system in which positions of desired packets cannot be easily determined, it is very inconvenient to provide broadcasting services according to the OMA-BCAST standard to users.